The Main Causes of Diarrhoea in Dogs

TUES OCT 30 2018

This article is written by one of our in-house veterinarians, Dr Carla Paszkowski BVSc.

Most dogs will experience diarrhoea at some point in their lives, and there are many causes for this unfortunate affliction. Some dogs with a sensitive stomach may experience 'on and off' bouts of chronic mild loose stool, which may respond to a sensitive stomach diet such as Royal Canin Digestive Care.

But sometimes the issue is acute and can affect healthy dogs. Your dog may just have small bouts of tummy upset and quickly improve, while others can become seriously unwell. If diarrhoea continues for an ongoing period, it can lead to weight loss, dehydration, and electrolyte depletion.

When to seek veterinary attention

You should seek immediate veterinary attention if:

  • The loose stool has persisted for more than 2 days
  • The stool is watery
  • There is any blood or mucus in the stool
  • Your dog is lethargic, off their food, or vomiting
  • Your dog is a puppy

The main causes of diarrhoea

1. Dietary Changes

A frequent source of diarrhoea in dogs is a sudden change in diet. Whether you’ve just run out of their favourite food or thought you’d try a tasty, new treat, suddenly changing a dog's diet can cause vomiting and diarrhoea. When introducing your pet to a new diet it is best to do so slowly to try and minimise any potential problems. read our article How to Transition to a New Pet Food for some more tips and tricks.

2. Eating something they shouldn't have

Dietary indiscretion, where your pooch has helped himself to something he shouldn't have, is another common cause of diarrhoea. Whether your dog has been rummaging through the garbage bin or has found a tasty morsel while out on a walk, both scenarios are likely to lead to an upset tummy. In this situation, feeding your dog a bland diet such as boiled chicken and white rice will often quickly help to resolve the diarrhoea. If however, the diarrhoea persists, your dog is vomiting frequently or seems generally unwell, it is important to seek veterinary advice and treatment.


3. Parasites

Another common reason for diarrhoea is parasite infection. Intestinal parasites like hookworms, whipworms, roundworms, coccidia and giardia will all cause diarrhoea. Dogs can pick up these parasites from eating contaminated meat, drinking from contaminated water, as well as coming into contact with infected animals or their faeces. Parasites are also easily transmitted from mothers to their pups, so it is especially important that puppies and pregnant or nursing females are treated for parasites regularly. If you'd like more information about protecting your dog or puppy from worms check out our Dog Worming Guide.


4. Food Sensitivities and Intolerances

Much like their human owners, dogs may also have dietary sensitivities or food intolerances which can result in diarrhoea. Intolerances in dogs generally develop over time and are associated with common proteins found in many commercially prepared dog foods including beef, dairy and wheat.

If you suspect that your dog may have a food allergy or intolerance, consult your vet regarding the best course of action. They may recommend a dietary trial using an elimination diet which is specifically formulated to be hypoallergenic. If the diarrhoea resolves during the feeding trial, it may indicate a food intolerance which usually requires a special dietary formulation to be fed long term.

Read more about hypoallergenic diets in our article What is the best Hypoallergenic Dog Food?


See our top diets for sensitive stomachs:

Royal Canin Digestive Care Range

Available for 'mini', 'medium', or 'maxi' dogs, this formula is highly digestible, making it perfect for dogs with occasional bouts of loose stool.

Hills Science Diet Sensitive Skin and Stomach

The sensitive stomach range from Hills is formulated with high quality protein and a gentle fibre blend to promote optimal nutrient absorption, easy digestion and healthy bowel function.

Advance Sensitive All Breed

This new formula from Advance is designed with Aussie pets in mind. It contains fish as the primary protein source and extra vitamins and antioxidants for digestive support.

Eukanuba Sensitive Skin and Stomach

This highly palatable digestive care diet from Eukanuba is made with easily digested rice, chicken and turkey and contains prebiotic fibres and beet pulp to help support a healthy digestive system.

5. Bacterial or viral infections

Bacterial and viral infections such as parvovirus can be another serious and life-threatening cause of diarrhoea in dogs, often requiring hospitalisation for treatment and recovery. To prevent these diseases and minimise your dog's risk of diarrhoea, always ensure all vaccinations are kept up to date, and keep any unvaccinated puppies away from other dogs or areas such as parks. Puppies tend to be the most at risk of parvovirus, and suffer the worst from these types of infections.

6. Extra-gastrointestinal causes

There are a myriad of other of serious causes of diarrhoea in dogs that are caused by other parts of the body. These might include pancreatic issues, liver disease, tumours, or blockage of parts of the gastrointestinal tract. In any case of persistent diarrhoea ensure you contact your vet and seek emergency treatment if your dog is unwell.